recursion

Question

 

What does fun2() do in general?

int fun(int x, int y) {     if (y == 0)   return 0;     return (x + fun(x, y-1)); }   int fun2(int a, int b) {     if (b == 0) return 1;     return fun(a, fun2(a, b-1)); }

Comments

power function i.e a^b.

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How?!

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Note that, fun(a,b) returns a*b as output

fun2(a,b) = fun (a,fun2(a,b-1)) = a * fun2(a,b-1) --------------> (1)

                                           = a* fun(a,fun2(a,b-2))

                                           = a * a * fun2(a,b-2) --------------> (2)

from 1 and 2, you can generalize, it as a^b.